1. Field of the Invention
The invention relates to a prefabricated aeration block for silo bases, which is cemented on a bottom plate with an air connection.
2. Prior Art
For emptying, mixing, or homogenizing bulk materials subject to fluidization in silos or partial areas thereof, the materials are in most cases aerated from below. The air is usually supplied via nozzles, mats, fabrics, sintered plastic materials, dry powdered metals, and porous bricks.
Depending on pressure and temperature load, intended use or flow behavior of the bulk materials, one or the other air supply may be more advantageous.
In homogenizing and mixing silos, aeration blocks have prevailed as particularly suitable and advantageous. However, the fixing of the aeration block on the silo base of reinforced concrete, and the durable, dustproof connection thereof with the air distribution system have always been a problem.
There are blocks that are attached in sheet metal casings, in which structure the sheet metal casings are always provided with an air connection piece. The total expense for material and working time for such constructions is very high.
A further development in this field is the multi-layer aeration block, wherein the air casing is replaced by a coarse-grained structure below a fine-grained top layer. In such a compact block, the air is supplied via a hollow space on the bottom side wherein an air supply line ends.
These blocks may be cemented on flat surfaces or in moist floor plaster. The demands on this cementing and the subsoil are very high. Close tolerances relating to alignment, properties, and consistency of the floor plaster, the ambient temperature, the processing temperature, and the age of the cement must be observed. Moreover, besides great skill of the assembling personnel, observance of a tight time schedule is necessary.
Outside these close tolerances, the quality of the aeration block is questionable. Cracks caused by heat, tension and shrinkage may in individual cases also affect the result.